Cooling system for internal-combustion engines



S. W. RUSHMORE COOLING SYSTEM FOR INTERNAL COMBUSTION ENGINES Oct-"4,1927. 1,644,088

Filed on. 27, 1924 INVENTOR ATTORNEY Patented Oct. 4, 1927.

SAMUEL w. nusn vronn, OF PLAINFIELD, new JnnsnY.

COOLING SYSTEM FOR INTERNL-COMBUTSTION ENGINES.

Application filed October 27, 1924. Serial No. 746,023.

My present invention relates to cooling systems of the general character disclosed in my prior Patent No. 1,378,724., of May 17, 1921. This patent disclosed .a type of cooling system which utilized amore or less conventional air cooled radiator so that it .operates as an .up-fiow steam condenser. The honeycomb of the condenser is disposed between the upper and lower water chambers of the radiator, the boiling water andsteam from the engine jacket being short circuited through the lower tank and pumped back to theacket. The steam and excess water from the j acket' usually enter the lower tanl:

=' in a somewhat turbulent condition and the steam escapes and rises in the honeycomb or the tubes to such height as may be necessary for condensation thereof. The condensate flows back by gravity in intimate heat exchange relation with the .upflowing current of steam. I v

This system, while entirely satisfactory under normal conditions ofengine operation, develops certain disadvantageous features of 7 operation, under .certainconditions, as when used on high power motor trucks and rail cars where the space available for the :con denser is relatively small. .This-is because the cross sectional .area of each condensing tube or passage :mustbe correspondingly small .in order to get the required area of cooling surface in such small space. In such small passages, the .down-flowing condensate interferes with the zupflowing, steam so that under certain conditions it is forced upwardly by the steam into the upper chamber of the radiator and, under accumulating steam pressure, it maybe then forced out through the 'blow-ofi or safety valve and in this way the supply of water in the system may be rapidly depleted.

I find, also,-that where the condensers are of relatively small condensing capacity so that :they have to work almost constantly at full or nearly full capacity, and where the excess of Water discharged with the steam from the jacket into the lowerchamber of the radiator is considerable, as where the supply to thejackets is greatly in excess of that ereauir d for properly cooling the engins, tailing alone, without any subefia tia'l overflow of water in liquid tor-m, turbulence in the lower chamber becomes great enough to forcelarge amounts ofwater, I

into the condensing tubes, further aggravatingthe ,difiicul'ty above. mentioned, causing excessive back pressures and raising the tem} perature in the engine jackets :above the uniform point desired th of the difficulties above mentioned may be overcome according to my present in vention, which includes means for preventing the accumulation ofany considerable amount of water in thelupper tank and for insuring that the entire condensing surface will operate at maximum efficiency before internal pressures can cause waste at the safety valve. I .I employ a circulating pump for returning water from. the lower tank to cooling jacketand in accordancewith my present invent-ion the header above the condensing tubes is connected to the intakelofthis pum by a pipe which may be .of relatively sma 1' cross section. The pipe from the lower tank to the pump is provided at thetank with an outlet orifice of relatively small cross section to limit the rate of flow .from the lower I tank to the pump. Inasmuch as the pump is purposely made of .a capacity considerably greater than that required .to handle the small amount of water which can pass to it through this orifice, there will be a certain amount of suction .in the drain pipe from the upper tank and any condensate forced into the upper chamber will readily .flowor be sucked back to the pump and by it returned to the engine jacket. Hence broadly stated, my invention includes a pumpldrawing water from both the upper and lower chambers. This is conducive .to uniform condenser pressures and the conventional blow-oil valve cannot become til the condenser is operating at ull capacity.

While my pump thus connected is adapted to takecare of a great excess of waterlin the circulating system and in the tubesan'd ,ciperative unupper chamber of the radiator, I'prefer to 1 ha-ve an intake orifice and to have it so proporn-cr ed that the water delivered there through will be gust sufficient to .811 ply the tastes jacket with a amma.

slightly greater than that needed to satisfy the maximum evaporative requirements of the engine. By thus regulating the size of the orifice,- the supply of water to the jacket becomes a simple boiler feeding problem, the jacket itself being nothing but a miniature steam boiler and water being fed thereto as fast as it can be boiled off.

The supply of water to the jacket through the restricted orifice should be constant and it will be evident that if the pump is permitted to develop any substantial vacuum in the pipe from the lower water tank, the flow of water through the orifice will be accelerated and the jacket will be over-supplied. The drain pipe from the upper header prevents the formation of any substantial vacuum in the outlet pipe from the lower water chamber and thus causes the'supply to the pump from the lower header to, be always determined by a gravitational flow, as limited by the size of the orifice.

Other expedients might be resorted to for preventing a vacuum in the pipe from the pump and as a matterof fact, a gravity feed is not essential to successful operation since if the pressure differential at opposite sides of the orifice is maintained always uniform, therate of flow through the orifice will remain uniform and the same result accom plished.

It is not a difficult matter to determine theflow necessary for supplying the jacket with slightly more than the maximum amount of water necessary and the difference between the amount required when the engine is running at high speed and the amount required when. the engine is idling is not very great. Hence in the preferred operation the surplus water flowing with the steam from the jacket to the radiator is never very great and is often practically negligible.

v The invention may be more fully understood from the following description in connection with the accompanying drawing, wherein-.

Fig.1 is a view in side elevation of an engine equipped with a cooling system embodying my present invention, the radiator being shown in section;

Fig 2 is a fragmentary detail illustrating an alternative method of controlling the flow of water to the pump. I

The cylinder jacket 10 of the engine 113 communicates at its upper forward end with an outlet pipe 12 down which water from the jacket is adapted to flow to the lower tank or header 13 of an upflow steam condenser. The con-denser includes above the tank 13 a honeycomb in the nature of a plurality of vertically disposed air cooled steam condensing tubes 14 of rela tively restricted cross section. These tubes ing pump 18 which returns the water to the engine jacket through a return pipe 19 delivering at the forward upper end of the jacket close to the outlet pipe 12.- Pump 18 is preferably a gear pump,

As more fully set forth in my copending application Ser. No. 746,024, filed on even date herewith, the relatively close juxtaposition of the inlet and outlet from the jacket 10 provides a low resistanceshort circui'td circulating path for water through the upper forward end of the jacket. By virtue of this construction, the main body of water in the jacket remains quiescent until boiling begins and the jacket water. is quickly raised to the desired temperature.

Two outlet valves are associated with the upper tank or header 15 of the radiator.

()ne of these valves 20 is in the nature of a breather permitting. escape of airfrom header 15, when pressures in the lower end of the condenser become excessive; Valve 20, however, is designed to automatically close when steam or water rising upwardly from the tubes 14 materially increases the temperature in header 15. The other valve 21is the conventional blow-01f or safety valve adapted to permit the escape of steam or water when excessive pressure obtainsin the header 15. V

This latter valve proves a source of considerable annoyance when the engine is Working under a heavy load, since the generation of an unusual amount of heat in the engine results in violent ebullition and steam evolution in the tank 13. The water in tank 13 is at this time in an extremely turbulent condition and consequently a considerable quantity of it is forced or blown up the tubes 14 into the header 15. The presence of this water even though it is in'a frothy or bub bling state, causes considerable back pressure in the condenser which is quickly'reli-eved by a discharge of steam and water through the safety valve '21. A great deal of the cooling fluid escapes in this mannerand it is partially to prevent such loss and the consequent inconvenience of frequently replenishing the water in the system that I make use of the drain pipe 22.

Pipe 22 prevents any water from being trapped in the header 15 and rapidly drains it back to the pipe 17 adjacent the intake of the pump 18. A restricted orifice 23 in the pipe 17 at the outlet fromtank 13 pred-eterthere an actual suction or subnormal pres sure developed in pipe 17 and transmitted through pipe 22 to header 15. In consequence oic'this-construction, pipe 22 not only serves to drain water from header but to suck water therefrom and from the tops of the tubes 14;, whereby condenser back pressure is quickly relieved Without any :loss of water from the system and pressure is main- 10 tained substantially constant throughout the entire body of the condenser.

It will be evident that while the safety valve 21 :may still become operative under very extreme conditions of overload, it cannot possibly operate before the condenser is working to full capacity and then only steam can escape so that the loss of water through this valve becomes negligible.

The orifice 23 in the pipe 17 is designed to permit the passage of a quantity of Water slightly in excess of the maximum evaporative requirements of the engine, the flow through the orifice being gravitational. In order that this flow be substantially constant, and entirely independent of the speed of the a pump, it is obviously necessary to provide some means ctor preventing a vacuum on the pipe L7, l-n-the present instance, it is accomplished :by the relatively restricted pipe 22 which in :addition to its above noted draining functioning, serves to prevent any sub stantial vacuum from :being created in pipe 17 or, in other words, serves :as a pressure equalizer to maintain a substantially constant pressure differential. Anadditional feature of importance .is :the fact that the rate of flow to the boiler is notonly independent of the speed of the pump, but is independent of the coolingeifect on the radiator and Will continue constant regardless of whether the car is running and'drawing a strongdraught of air through the radiator :or whether the engine is idling with a consequent slight cooling effect.

It is to be borne in mind that the supply of Water through orifice 2-3 to the pump is ample at all times to satisfy the requirements of the jacket. The slight excess which is sometimes drawn through pipe 22 will be introduced into the jacket at a time when ebullition is very violent and consequently when such excess can do no harm.

In the particular embodiment of the invention which I have illustrated, the pipe 22 serves the double function of a drain pipe and a pressureequalizer, but both of these functions might be. separately served by 0th1-111G&1'lS-.' The regulation of the flow of water to the jacket :10 maybe and preferably is reduced to a simple boiler feeding problem, it being necessary merely vto supply slightly more water :than .can 'be boiled off when the heat evolution in the engine is at a maximum. Broadly -.considered, however. the usefulness of the apparatus is not limited to this preferred method ofoperation. The apparatuswill continue to operate by the boiling and condensing cycle and the intake from the upper chamber will be useful even where there isa great excess of water in the entire circulating system including radiator tubes and upper chamber,

In Fig. 2, I have illustrated a slightly modified form of the device in which the flow of water from tank 13 through pipe -1-7 to the ,pump is controlled by a manually adjustable valve 25 instead of by the orifice 23. The valve possesses advantages over the orifice in that it :may be adjusted to compensate for wear on the pump, or for extreme weather conditions.

I claim:

-1. In a cooling system for internal combustion engines, a force feed water circu lating system of small heat radiatingcapacity serially including a water jacket, a water outlet from said jacket, a water container to which said outlet is connectedand a return conduit including a pump between said container and jacket in combination with-anair cooled element of, large radiating capacity above said water container, la chamberabove the air cooled element into which hot water is adapted :to escaperand means for draining the water from said chamber back to the cooling water circuit.

V ,2, In a cooling system for internal combustionengines, a force feed WfltGIwCll'Oll lating system of small heat radiatingcapacwater is adapted to escape and means :for

draining the water from said chamber back to the cooling water circuit, said means including a drain :pipe opening into the bot.- tom of the chamber and connected 'tosthe return conduit from the container.

3.1-n a cooling system for internal co1nbustion engines. a force ,feed water circulating system of small heat radiating capacity serially including a water jacket, a water outlet from said jacket, a water container To which said outlet is connected and a return conduit including a pump between said container and acket incombination with an air cooled element of large radiating capacity above said water container, a chamber above the air cooled=element into which hot water is adapted to escape and means for draining the water from said chamber back to the from the container, said return conduit being of restricted cross-section atthe container whereby the pump will create a low pressure in the drain pipe.

4. In a cooling system for internal combustion engines, a jacketed element to be cooled, an upfiow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said conduit, said condenser including a plurality of restricted air cooled passages above the tank and a chamber into which the upper ends of the passages open in combination with means for preventing the collection of water in the upper chamber and for draining the water from the upper chamber back to the system,

5. In a cooling system "for internal combustion engines, a jacketed element to be cooled, an upflow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said conduit, said condenser including a plurality of restricted air cooled passages above the tank and a chamber into which the upper ends of the passages open in combination with an outlet pipe from the upper chamber and means whereby the pump produces a suction in the outlet pipe. 7

6. In a cooling system for internal combustion engines, a jacketed element to be cooled, an upflow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said conduit, said con denser including a plurality of restricted air cooled passages above the tank and a chamber into which the upper ends of the passages open in combination with a drain pipe from the upper chamber to the return conduit, said return conduit having arestricted flow portion therein between the tank and the pump, said drain pipe delivering into the return conduit between the restricted portion and the pump. I

7. In a cooling system for internal combution engines, a acketed element to be cooled, an upflow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said. conduit, said condenser iucluding a plural ty of restricted air cooled passages above the tank and a chamber into which the upper ends of the passages open in combination with a restricted flow portion in the return pipe to limit the amount of water draining from the tank to the pump to a quantity considerably less than the capacity of the pump and means whereby suction in the return conduit caused by such failure oi water supply from the upper chamber.

1,e44,ose

tank operates .to relieve pressures in the 8. In a cooling system for internal combustion engines, a jacketed element to be cooled, an upfiow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuitec, a return conduit from the tank to the jacket, a pump in said conduit, said condenser including a plurality of restricted air cooled passages above the tank and a chamber into which the upper ends of the passages open, said return pipe including a restricted orifice to limit the amount of water draining from the tank to the pump to a quantity considerably less than the capacity of the pump and means whereby suction in the return conduit caused by such failure of water supply from the tank operates to prevent the accumulation o'twater in the upper chamber.

9. In a cooling system for internal combustion engines, a jacketed element to be cooled, an upllow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said conduit, said condenser including a plurality of restricted air cooled passages above the tank and a chamber into which the upper ends of the passages open, said return pipe including a restricted orifice to limit the amount of water draining from the tank to the pump to a quantity considerably less than the capacity of the pump and means whereby suction in the return conduit caused by such failure rot water supply from the tank operates to equalize pressures throughout the condenser.

10. In a cooling system for internal combustion engines, a jacketed. element to be cooled, an upflow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuited, a return conduit frou'i the tank to the jacket, a pumpin said conduit, said condenser including a plurality restricted air cooled passages above the tank and a chamber into which the upper ends or the pa:- sages open, said return pipe including a re stricted orifice to limit the amount of water draining from the tank to the pump to a quantity considerably lessthan the capacity of the pump and means whereby suction in the return conduit caused by such failure of water supply from the tank operates to prevent back pressure in the condenser.

11. In a cooling system for internal combustion engines, a force feed water circulating system of small heat dissipating capacity serially including a water jacket, a water outlet from said jacket, a radiator including a water container to which said outlet is connected and in which variable loo amounts" of excess water may be circulated, a return conduit including a pump between the container and jacket, a restriction in the conduit betweenthe container and the pump and a vacuum preventing connection to said conduit between the restriction and the pump whereby the amount of water flowing through the restriction will be substantially constant regardless of the supply as determined by the boiling and condensing rates and regardless of the speed or capacity of the pump.

12. In a cooling system for internal com bustion engines, a force feed water circulating system of small heat radiating capacity serially includinga water jacket, a water outlet from the jacket, a radiator including a water container to which the outlet is connected and in which variable amounts of excess water may be circulated, and a return conduit including a pump between said container and jacket, in combination with an air cooled element of large radiating capacity above said water container and means for rendering the rate of flow of water through the return conduit independent of the supply as determined by the boiling and condensing rates and independent 0 the speed of the pump.

13. In a cooling system for internal combustion engines, a jacketed element 'to be cooled, an upflow air cooled steam condenser including a bot-tom tank through 'which water from the j acket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said conduit and means for gravitationally feeding water from the tank to the pump at a predetermined rate and independently of the speed of the pump.

14. In a cooling system for internal combustion engines, a jacketed element to be cooled, an upflow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuited, a return conduitfrom the tank to the jacket, a pump in said conduit,

said conduit including a restricted orifice limiting the flow of water from the tank to the pump to an amount slightly in excess of the evaporative requirements of the engine.

15. In a cooling system for internal combustion engines, a jacketed elementto be cooled, an upflow air cooled steam condenser .including a bottom tank through which water from the acket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said conduit, said conduit including a restricted orifice limiting the flow of Water from the tank to the pump to an amount slightly in excess of the evaporative requirements of the engine, and means for preventing a vacuum in the conduit between the pump and the orifice.

16. In a cooling system for internal combustion engines, a jacketed element to be the acket, a pump in said conduit, said con- 'duit including a restricted orifice limiting the flow of water from'the tank to the pump to an amount slightly in excess of the evaporative requirements of the engine, and means for maintaining a constant pressure diflerential on opposite sides of the orifice.

'17. In a cooling system for internal combustion engines, a jacketed element to be cooled, an upflow air cooled steam condenser including a bottom tank through which Water from the jacket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said conduit, said conduit including a restricted orifice limiting the'flow of water from the tank to the pump to an amount slightly in excess of the evaporative requirements of the engine, and means for adjusting the size of the orifice.

. 18. In a cooling system for internal combustion engines, a acketed element to be cooled, an upflow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump in said conduit, and

including a bottom tank through which a water from the jacket is adapted to be short circuited, a return conduit from the tank to the jacket, a pump 'in said conduit, and

means for maintaininga predetermined constant rate of water flow from the tank to the pump slightly in excess of the maximum evaporative requirements of the jacketed element tobe' cooled, said means being inde-.

pendentot the pressure in the tank.

20. In a cooling system for internal combustion engines, a jacketed element to be cooled, an .upflow air cooled steam condenser including a bottom tank through which water from the jacket is adapted to be short circuit-ed, a return conduit from the tank to the jacket, a pump in said'conduit, and means for maintaining a predetermined constant rate of water flow from the tank to the pump slightly in excess of the maximum evaporative requirements of the jacketed element to be cooled, said means being independent of the speed of the pump. v p

21. In a cooling system for internal combustion engines, a jacketed element to be cooled, an upflow air cooled steam condenser including a bottom tank through which Water from the jacketis adapted to be short circuited a return conduit from the tank to the jacket, :1 pump in said conduit, and means for maintaining a predetermined constant rate of Water flow from the tank to the pump slightly in excess of the maximum eveporative requirements of the jacketed element to be cooled, said means being independent of the cooling efiect on the condenser.

Signed at P1ainfie1d,-in the county of Union, and State of New Jersey, this 25th day of October, A. D. 1924;.

SAMUEL -W. RUSHMORE. 

